Method of assembling the actuating mechanism for air-blast circuit breakers



Aug. 3, 1965 TETSUO KOBAYASHI ETAL 3,198,917

METHOD OF ASSEMBLING THE ACTUATING MECHANISM FOR AIR-BLAST CIRCUITBREAKERS Filed March 19, 1965 UN/En RS TeTsuo Koboy cniohi a o BY ml),m-mRnEy United States Patent 3,198,917 METHOD 6F ASSEMELHNG THEACTUATING MECHANISM FGR AIR-BLAST CIRCUIT BREAKERS Tetsuo Kohayashi andZenichi Nakano, Hitachi-sin,

Japan, assignors to Hitachi, Ltd, Tokyo, Japan, a corporation of JapanFiled Mar. 19, 1%3, Ser. No. 266,290 Qiaims priority, appiication Japan,Apr. 26, 1962, 37/ 16,006 1 tllaiin. (@l. Nth-143) The present inventionrelates to the assembling of the actuating mechanism for air-blastcircuit breakers of the type including an air reservoir, at least oneporcelain bushing upstanding from said air reservoir for supporting aninterrupter unit, an operating unit and an opening-andclosing controlvalve operable to supply and exhaust air to and from the operating unitand also serving as a vent tube, an insulating rod vertically extendingthrough said porcelain bushing for operating said control valve, apiston-cylinder assembly arranged on the ground side in said airreservoir at one end thereof, and a link mechanism arranged in said airreservoir and interconnecting the piston of said piston-cylinderassembly and the bottom of said insulating rod for mechanicallyactuating said control valve upon energization of said piston-cylinderassembly, said actuating mechanism including said link mechanism andassociated parts such as hearing brackets therefor.

The present invention has for its object to provide a method ofassembling such actuating mechanism in the air reservoir without anyneed of forming access holes in the wall of the reservoir for theassembling purpose thereby minimizing the use of packing elements on theair reservoir and hence the possibility of air leakage therefrom whileproviding a simple and neat appearance to the air reservoir.

In brief, this objective is attained, according to the presentinvention, by first inserting the link mechanism together with the drivepiston into the interior of the air reservoir through the cylinderbarrel formed at one end thereof and then assembling the mechanism withthe hearing bracket conveniently through the vent aperture formed in thereservoir wall for the purpose of charging air from the air reservoir tothe interrupter unit.

Other objects, features and advantages of this invention will beapparent from the following description when taken in conjunction withthe accompanying drawing, which diagrammatically illustrates onepractical example of the invention and in which:

FIG. 1 is a longitudinal vertical cross section of an air-blast circuitbreaker actuating mechanism as assembled by the method of the invention;and

FIGS. 2 and 3 are views similar to FIG. 1 illustrating different stagesof the method of assembling the actuating mechanism.

In the drawing, like reference characters designate like partsthroughout the several figures. Referring first to FIG. 1, whichillustrates a single-phase air-blast circuit breaker having twointerrupter units, the reference nu- Lmerals 2 and 22 designaterespective vent apertures formed in the wall of the air reservoir 1 forsupplying air therefrom to the two respective interrupter units of theair-blast circuit breaker. Reference numeral 3 designates a cylinderformed at one end of the air reservoir for receiving a drive piston 11.Bearing brackets 4 and 24 are inserted into the air reservoir throughthe respective vent apertures 2 and 22 and include seating plates 5 and25, respectively, which seat on the vent apertures in sealing engagementtherewith. Connected to the vent apertures 2 and 22 are porcelainbushings 6 and 26 which support the respective interrupter units ininsulating relation "ice thereto and also serve as vent pipes.Insulating rods 7 and 27 extend vertically through the respectiveporcelain bushings 6 and 26 for the purpose of actuating the interrupterunits. Bell crank levers 8 and 28 are pivotally secured as at 9 to therespective bearing brackets 4 and 24 with one arm of each of the leversconnected with the bottom of the associated insulating rod 7 or 27. Anactuating link 10 is connected at one end with the drive piston 11 andat the other end with the other arm of the bell crank lever 8. Anotheractuating link 20 is connected at one end to the link 10 and at theother end to the other arm of the bell crank lever 28. A compressionspring 12 is arranged in the cylinder 3 between the drive piston and thecylinder cover, as illustrated. Provided outside of the air reservoir isa solenoid valve 13 for controlling the actuating mechanism and havingan exhaust port 14. Air conduits 15 and 16 are arranged to connect thesolenoid valve with the cylinder and the air reservoir, respectively.

In FIG. 1, the actuating mechanism is shown with its parts in positionto open the interrupter unit. Namely, the solenoid valve 13 isdeenergized to communicate the cylinder with the exhaust port 14 by wayof the air conduit 15. Accordingly, the drive piston 11 is in its leftend position under the air pressure in the air reservoir,

which acts upon the piston in the direction indicated by the arrows, andthe insulating rods 7, 27 are in bottom position under the pull of theactuating links 10, 20 acting through the respective bell crank levers8, 28.

The closing operation of the interrupter units is as follows. Thesolenoid valve 13 is energized to close the exhaust port 14 whileallowing flow of air from the air reservoir 1 through air conduit 16,solenoid valve 13 and air conduit 15 into the cylinder 3 so that thepiston 11 is moved to the right by the air pressure acting in the samedirection as the compression spring 12. The piston 11 thus acts throughactuating links 10, 20 and associated bell crank levers 8, 28 to forcethe respective insulating rods upwardly to close the interrupter unitsmounted on top of the porcelain bushings 6 and 26, respectively.

With this arrangement, since, as illustrated in FIG. 1, the insulatingrods 7, 27 operable for opening and closing the respective interrupterunits extend vertically through the porcelain bushings 6 and areconnected at the bottom with the drive piston 11 through theintermediary of the link mechanism arranged in the air reservoir, theair-blast circuit breaker has an extraordinarily simple and neatappearance and is free from the danger that the actuating mechanism bedamaged by external forces as with the case of conventional air-blastcircuit breakers having their actuating mechanism arranged outside ofthe air reservoir.

However, the arrangement of such actuating mechanism accommodated in theair reservoir 1 has been extremely dllTlClllt to assemble its componentstherein thus requiring the provision of access holes in the reservoirwall for the assembling purpose and hence of coverings therefor withpacking means to sealingly close the access holes.

According to the present invention, there is provided a method ofassembling the actuating mechanism in the air reservoir in a simplemanner and without forming any access holes for the purpose.

The assembling method of the present invention will now be described indetail with reference to FIGS. 2 and 3, which illustrate the differentstages of the assembling procedure. At the first, bell crank lever 8,actuating link It) and drive piston 11 are interconnected and insertedinto the air reservoir 1 through the cylinder 3 at one end thereof andthe bell crank lever 8 is pulled out of the reservoir from outsidethrough one of the vent apertures 2. The bearing bracket 4 andinsulating rod 7 are pivotally connected to the lever 8 at its oppositeends exteriorly 3 of the reservoir and then inserted together with thelever 8 into the reservoir 1 through the vent aperture 2. The seatingplate 5 of the bearing bracket 4 is fixed to the vent aperture 2 andporcelain bushing 6 is secured to the plate 5 to extend verticallytherefrom.

In assembling the actuating mechanism for a singlephase air-blastcircuit breaker having two interrupter units as illustrated herein, theother bell crank lever 28 previously inserted into the air reservoirtogether with the actuating link 20 is pulled out of the reservoir (FIG.3) through the vent aperture 22, after the lever 8 and associated partshave been assembled, and then is assembled with the bearing bracket 24and insulating rod 27. The assembly is inserted into the air reservoirand the seating plate 25 of bearing bracket 24 is fixed to the ventaperture. Finally porcelain bushing 25 is secured to the plate 25 toextend Vertically therefrom.

It will be understood that the actuating mechanism for three interrupterunits supported by respective porcelain bushings upstanding from asingle air reservoir may also be assembled progressively in quite thesame manner as described above.

It will be apparent from the foregoing that according to the presentinvention the actuating mechanism of the type described can be assembledwith ease by making use of the vent apertures, formed in the airreservoir and communicating with the respective interrupter units, andthe actuating cylinder formed at one end of the air res ervoir. Thus,there is no need of forming access holes in the Wall of the airreservoir for the assembling purpose and the use of packing elements onthe air reservoir and hence the possibility of air leakage therefrom areminimized.

Having fully described our invention, it is to be understood that we donot wish to be limited to the details set 4 forth, but our invention isof the full scope of the appended claim.

What is claimed is:

In an air-blast circuit breaker of the type including an air reservoir,at least one porcelain bushing upstanding from said air reservoir forsupporting an interrupter unit and also serving as a vent tube, aninsulating rod vertically extending through said porcelain bushing foractuating said interrupter unit, a piston-cylinder assembly arranged atone end of said air reservoir, and a link mechanism arranged in said airreservoir and including an actuating link connected at one end with thepiston of said piston-cylinder assembly and a bell crank lever connectedat one end with the other end of said actuating link and at the otherend with the bottom of said insulating, rod, a method of assembling theactuating mechanism including said link mechanism and a bearing brackettherefor having a seating plate comprising inserting said actuating linkand said bell crank lever into the air reservoir through the cylinder ofsaid piston-cylinder assembly, pulling said bell crank lever out of thevent aperture formed in the wall of said air reservoir and to which saidporcelain bushing is to be secured, assembling the hearing bracket tosaid bell crank lever exterlorly of said air reservoir, inserting theparts thus assembled into the interior of said air reservoir throughsaid vent aperture, fixing the seating plate of the bearing bracket tosaid vent aperture, and securing said porcelain bushing to the top ofsaid seating plate to extend vertically therefrom, said steps beingrepeated progressively as many times as correspond to the number of saidporcelain bushings.

No references cited.

BERNARD A. GILHEANY, Primary Examiner.

